1. Field of the Invention
The present application is directed to heating beverage, and is more specifically related to heating devices for hot beverage containers having insulating sleeves.
2. Description of the Related Art
Beverages such as coffee, tea and the like are best enjoyed when consumed hot. When such beverages are served in a conventional drinking cup they tend to cool relatively rapidly. This is particularly true when the beverage is served in a paper drinking cup of the character used in many drive-through restaurants.
Devices of several different designs have been suggested in the past for warming consumable liquids and for maintaining the elevated temperature of the liquid. Exemplary of one such device is that described in U.S. Pat. No. 6,121,585 to Dam. The invention described in the Dam patent comprises a beverage cup and cup holder system. The Dam beverage cup includes a sleeve, a liner and a base that includes a plate, a heating element and a pair of spring terminals. The base further includes a contact ring and a contact disk. The cup holder, which is adapted to mate with the base of the beverage cup, has recessed land areas which lie below a plane of the support for the beverage cup and are electrically isolated from each other. The cup holder includes spring contacts which extend into the recessed land areas and are adapted to receive connections from an external source of electrical current. The beverage cup, when filled with a hot beverage, is placed into the cup holder. As the beverage cup is placed into the cup holder, the contact disk and contact ring automatically align with the recessed land areas and make contact with the spring contacts. The heating element of the device maintains a beverage at a desirable equilibrium temperature for an extended period of time.
Another prior art device past for warming consumable liquids is described in U.S. Pat. No. 4,463,664 issued to Peace. The Peace invention provides a receptacle having a thermally nonconductive exterior to retain the heat of liquids, and a durable heat-conductive interior portion to reside in heat-conductive relation with a source of warming heat, so as to impart heat to the contents of the receptacle. The receptacle of the Peace device comprises a heat-conductive liner including a bottom portion and an upwardly extending wall portion, and a heat-insulating sleeve surrounding the wall portion of the liner, the bottom portion of the liner being exposed for direct contact with a heat source. The nonconductive sleeve surrounding the wall portion of the conductive liner has an open bottom which terminates a short distance below the bottom portion of the liner in surrounding yet spaced-apart relation to the bottom portion, in order to isolate the sleeve from the heat source.
U.S. Pat. No. 8,274,016 to Montana discloses a cup holder having a heating surface that is configured to receive a cardboard cup. The cup holder has an outside surface that is concentric with the heating surface. A heating element is disposed between the heating surface and the outside surface, and the heating element is configured to heat the heating surface. Insulation is located between the heating surface and the outside surface, and the insulation may be configured to maintain the outside surface at an outside temperature lower than a heating temperature of the heating surface. The cup holder has a pressure-sensitive switch located in a bottom portion of the heating surface. The pressure sensitive switch allows a current to run through the heating element in response to the cardboard cup exerting pressure on the pressure-sensitive switch. Although an advance, Montana does not discloses an effective system for heating a cardboard cup having an insulating sleeve. Moreover, Montana does not disclose a system for heating a beverage through the bottom wall of a cardboard cup because the pressure sensitive switch disclosed in Montana is located at the bottom of the cup holder wherein it is engaged by the bottom wall of a cardboard cup inserted into the cup holder.
Thus, there remains a need for portable heating devices for hot beverage containers such as paper cups having insulating sleeves. There also remains a need for heating devices that are designed for receiving paper cups having insulating sleeves. There also remains a need for heating devices that heat liquids through the bottom wall of a paper cup.